Passenger vehicles are generally transported from the manufacturer to the dealer on tractor-trailer trucks commonly referred to in the industry as car haul carriers. These car haul carriers usually have a number of vehicle supporting track assemblies which can be adjustably positioned in the carrier to support different vehicle loads. The vehicles to be transported are supported on top of the supporting track assemblies for transport. To keep the vehicles on the track assemblies, they must be tied down. This tying down of the vehicles is accomplished with a plurality of tie down mechanisms to which a flexible tie down member such as a chain or cable is attached so that the tie down member can be hooked onto the vehicle and then the tie down member wound onto the tie down mechanism to take up the slack in it and force the vehicle down onto the top of the supporting track section to keep it in position.
Prior art tie down mechanisms generally included a tie down shaft rotatably mounted on the supporting track section to which one end of the flexible tie down member is attached so that it can be wound around the tie down shaft to take up the slack in the flexible tie down member and force the vehicle down onto the top of the supporting track assembly. One end of the tie down shaft has a driving head on it with holes so that the operator can insert a tie down bar in these holes and use it to rotate the driving head and tie down shaft. To keep the tie down shaft in position while tying down a vehicle, the driving head usually had ratchet teeth on it engaged by a ratchet pawl. The ratchet pawl was manually released when the vehicles were being untied for unloading.
These prior art tie down mechanisms have had a number of problems associated with them. One of these problems is that they required the operator to exert considerable effort to tighten the flexible tie down member sufficiently to properly tie down a vehicle. This was so even though the tie down bar was about three feet long. As a result, operators have frequently been injured due to overexertion in trying to properly tie down a vehicle. Another problem has been associated with the untying of the vehicle. To untie a vehicle, it was necessary for the operator to rotate the driving head sufficiently with the tie down bar to release the pressure on the ratchet pawl so that it could be released and then manually disengage the ratchet pawl while holding the tie down bar against the full tie down force load on the tie down shaft. The operator sometimes let the bar slip out of his grasp or could not maintain his control over the tie down bar so that the tie down bar was rapidly moved by the load. This frequently resulted in injury to the operator and/or damage to the vehicle.